Table 1.

Characteristics of comparative trials included in the meta-analysis

Reference	Year	Type of trial	Study quality score	Study population/setting	Method for the micro-biological diagnosis of pneumonia	Length of ICU stay (days)	Duration of mechanical ventilation (days)	Studied drug/dosage	Drug administration	Mode of administration	ITT	No. of patients clinically evaluable
Wood et al. [21]	2002	Double-blind, placebo-controlled RCT	5	Mechanically ventilated for >2 days, trauma patients with >1 risk factor for post-traumatic pneumonia; ICU; USA	Bronchoalveolar lavage	19 ± 11 vs 21 ± 12	16 ± 11 vs 18 ± 13	Ceftazidime: 250 mg every 12 hours	For 7 days	Aerosolized	59	20 vs 20
Rouby et al. [19]	1994	Non-randomized clinical trial	NA	Mechanically ventilated for >3 days; surgical ICU; France	Bronchoalveolar lavage	No data	Survivors: 18 ± 12 vs 12 ± 14 Non-survivors: 9 ± 5 vs 8 ± 4	Colistin: 200,000 units every 3 h	For 2 weeks	Endotracheal instillation	598	347 vs 251
Rathgeber et al. [18]	1993	RCT	2	Mechanically ventilated; ICU; Germany	Bronchial secretions	No data	17 vs 13	Tobramycin: 80 mg every 6 hours	Until the time of extubation	Aerosolized	69	29 vs 40
Lode et al. [17]	1992	Double-blind, placebo-controlled, RCT	2	Mechanically ventilated for >3 days; 5 European ICUs	No data	No data	No data	Gentamicin: 40 mg every 6 hours	Until the time of extubation (<14 days)	Endotracheal instillation	199	85 vs 77
Vogel et al. [20]	1981	Non-randomized, controlled clinical trial	NA	Mechanically ventilated for >5 days; medical ICU; Germany	Tracheal aspirates	No data	8.3 vs 7.4	Gentamicin: 40 mg every 6 hours	For 2 weeks	Endotracheal instillation	40	20 vs 20
Klick et al. [15]	1975	Double-blind, placebo-controlled, non-randomized clinical trial	NA	Mechanically ventilated or not; respiratory-surgical ICU; USA	Sputum; Tracheal aspirates	5.1 vs 5.3	No data	Polymyxin B: 2.5 mg/kg body weight/day in 6 divided doses	Throughout the entire ICU stay	Aerosolized	744	355 vs 337
Klatersky et al. [13]	1974	Placebo-controlled RCT	3	Tracheostomised neurosurgical ICU; Belgium	Sputum; tracheal aspirates; bronchial secretions	19.9 vs 14.7	NA	Gentamicin: 80 mg every 8 hours	Throughout the entire ICU stay	Endotracheal instillation	110	43 vs 42
Greenfield et al. [11]	1973	RCT	1	Mechanically ventilated or not, high-risk patients; respiratory-surgical ICU; USA	Sputum	9.0 (median 6.0) vs 7.6 (median 6.0)	No data	Polymyxin B: 2.5 mg/kg body weight/day in 6 divided doses	Throughout the entire ICU stay	Aerosolized	58	33 vs 25

Values are for the group receiving prophylactic antibiotics by the respiratory tract versus (vs) the control group. ICU, intensive care unit; ITT, intention-to-treat; NA, non applicable; RCT, randomized controlled trial.